Method and apparatus for humidifying hydrophilic materials



S. W. SFEERS May 23, 1967 METHOD AND APPARATUS FOR HUMIDIFYINGHYDROPHILIC MATERIALS Filed Dec. 9, .1964

1. 1 um. uw Afin/Jj@ af @Tv e NK i 2y mw n @j f1 MN w Q WQ United StatesPatent 3 320,676 METHOD AND APPARATUS FOR HUMIDIFYING HYDROPHILICMATERIALS Stewart W. Speer-s, Upper Darby, Pa., assignor to FMCCorporation, Philadelphia, Pa., a corporation of Dela- Ware Filed Dec.9, 1964, ser. N0. 417,007 13 Claims. (ci. 34-23) This application is acontinuation-in-part of my application Ser. No. 396,165, filed Sept. 14,1964, and now abandoned.

This invention relates to an improved method and appa-ratus for applyingmoisture to traveling hydrophilic materials, and especially forhumidifying running webs of sheet materials.

Various materials and articles containing moisture lose moisture duringmanufacture, conversion and use so that moisture has to be restored tofacilitate their handling and use. For example when paper and cellophaneare manufactured, it is frequently not possible to control the drying ofthe sheet so that the moisture content of the product has the desiredvalue. When paperboard is to be -creased and folded for box manufacture,the moisture content must be controlled or otherwise the board maycrack. Paper caps and paper containers must have a regulated moisturecontent to enable them to have required dimensions. Further, textilefabrics, leather and the like must have controlled moisture content forproper finishing, cutting and sewing. In addition when any of thehydrophilic material-s is printed or coated with inks or lacquers thatrequire heat for hardening and drying, there is always a loss ofmoisture in the base materia-l which must be restored.

Generally, satisfactory humidification of hydrophilic materials can beachieved with methods and apparatus as described in my U.S. Patents2,906,205 and 2,973,635 and the U.S. patent to I. D. Conti 2,718,065.However, when such known systems are employed for restoring largequantities of moisture and/ or when high speed humidifying operationsare attempted, the generally fragile material must often make more thanone pass through the h-umidifying treatment and/ or a comparativelylarge and expensive humidifying apparatus is required.

Attempts to compensate for the inadequacies of the known humidifyin-gsystems by surface wetting of the hydrophilic materials before and asthey enter the humidifying apparatus have not proven to be successful.For example, prewetting of the hydrophilic material by means of a waterbath provided only a negligible improvement in the amount of waterretained by the material and was often accompanied by non-uniformhumidification. On the other hand, water sprayed onto the hydrophilicmaterial as it entered the humidifying apparatus flashed off before ithad an opportunity to penetrate, while Water sprayed into the steamatmosphere within the humidifying apparatus resulted in excessive andundesired water spotting of the material. Accordingly, a primary objectof this invention is to provide an improved and mo-re satisfactorymethod and apparatus for humidifying hydrophilic materials.

Another object of this invention is the provision of an improved methodand apparatus for rapidly and uniformly imparting moisture tohydrophilic materials.

Still another object is the provision of an improved method andapparatus for imparting comparatively large quantities of water tohydrophilic materials which are moving at high speeds and withoutinvolving any waters-potting thereof.

These and other objects and advantages will be apparent from thefollowing description.

FIGURE 1 is a vertical section taken longitudinally through thehumidifying apparatus of the present invention;

FIGURE 2 is a transverse section taken along the line II-II of FIGURE l;and

FIGURE 3 is an end view of the apparatus shown in FIGURE 1.

These objects are accomplished in accordance with the present inventionby a method and apparatus wherein water in the form of a fine mist isapplied Ion and adjacent to a hydrophilic material after which thematerial, along with the layer of water mist is passed into and througha generally confined area or chamber where it is subjected to a humidvaporous medium or atmosphere, such as wet or moist steam. This humidvaporous medium travels concurrently with the hydrophilic material and,in addition to itself imparting moisture to the material, causes theapplied accompanying layer of water mist to penetrate rapidly and beabsorbed into the material. This humidified hydrophilic material is thenseparated from the spent and excess humid vaporous medium and saturatedair at it leaves the chamber and is rapidly cooled by the ambientatmosphere or a chill roll so as to retain the moisture which it hasassumed.

In lieu of or in addition to the initial application of the fine watermist, the hydrophilic material may be subjected to a `tine mist of wateras it leaves the humidifying ch-amber and before it has been cooled. Inboth of these instances the hydrophilic material would pass through thehumid vaporous medium and would therefore be in a hot or warm conditionwhen it leaves the chamber. It was expected that the water mist providedat this location might perhaps be drawn into the area at which thehumidified material is separated from the spent and excess humidvaporous medium and thus be removed before it has any opportunity toprovide any benefit. Further, it was eX- pectecl that any of such watermist which might settle .upon the humidifed material would result inwater spotting and other signs of non-uniform humidification.Surprisingly, however, it was found that the water mist applied to thehumidified material at this location was rapidly and uniformly assumedand retained by the material.

In general, the moisture content of the humidified material is greaterwhen the water mist is applied before rather than after such materialleaves the humidifying chamber. The most significant advantage, however,is that large quantities of moisture, such as 10% to 12% and more can beintroduced into a hydrophilic material when such material is treatedwith mists of water both as it enters and leaves the humidifyingchamber. The introduction of such large quantities of moisture is notaccompanied by any water spotting or other signs of nonuniformapplication. Moreover, the modified procedure is efficient andeconomical since the residual heat of the humidiiied material isutilized, and thus dissipated, as it assists the last applied mist ofwater in penetrating into the material.

The apparatus of the present invention includes a chamber havingseparate and spaced entrance and exit openings for the hydrophilicmaterial to pass therethrough and means, such as an `atomizer, forapplying water in the form of a mist on and adjacent to at least oneside of the material as it approaches and enters and/or as it leaves thechamber. Within the chamber supply means, including a series of nozzlesor jets, are provided for directing a humid vaporous medium toward thehydrophilic material. Exhaust or suction ducts are positioned within thechamber, along the opposite sides of its exit, for separating andremoving the spent and excess humidifying medium and saturated air fromalong side of the humidified material as the latter leaves the chamber.

For satisfactory practice of the method of the invention, it isessential that water, in the form of a mist or fog, be applied to thehydrophilic material while such material is -outside of the humidifyingchamber. Any attempt to spray water within the chamber would result incondensation on the material which is being treated. Secondly, it isnecessary that at least one layer of water mist accompany thehydrophilic material as it enters into and travels within thehumidifying chamber and/or immedi ately after such material leaves thechamber. This is, of course, achieved by drawing such layer of watermist into the chamber by the-exhaust or suction ducts which are locatedadjacent to the chamber exit opening.

The method and apparatus of the present invention are adapted for 4usewith a variety of Vhydrophilic materials, such as paper and paperboard,whether made by the kraft or sulte or other process, also glassine,textiles containing hydrophilic fibers, and other hydrophilic films, asfor example films made from cellophane and cellulose ethers of thealkali-soluble or water-soluble type, alginates, casein, glue and thelike. The material to be treated, which is referred to in the followingdetailed description las a sheet material, may be in the form of a web,tube, band, ribbon, strip or in the form of individual sheets, pieces,parts, bags, shaped bodies and laminated structures formed in whole orin part of any of the moisture-containing materials noted above. In thelatter instance, in which individual articles are being humidified, thearticles are preferably carried upon a conveyor or similar device.

The apparatus of the presentinvention may be ernployed by itself or incombination with other equipment which yperforms such operations on thehydrophilic material so as to require humidification or rehumidicationthereof to render the mater suitable for its intended use or for furtherprocessing. For example, this humidifying apparatus maybe used alone inadjusting the moisture content of a hydrophilic material which has beensubjected to varying conditions during transit or storage. A1-ternatively, the humidifying apparatus may be employed `with otherequipment such as a conventional drying or coating system forreintroducing moisture into a material.

Referring now to the drawing the apparatus of the present inventionincludes a chamber having top and bot- .tom walls 17 and 19, side walls21 and 23 and end walls 25 and 27. An entrance opening to the chamber isformed at 29 in the end wall 25 and a similar but separate exit openingis provided at 31 in the end wall 27. The sheet material which is to behumidied is indicated at 33 and is guided to and from the chamber 15 -byrolls 35, 36 and 37, the latter of which may be chilled to rapidly coolthe sheet material 33.

Positioned outside of the chamber 15, along one end perhaps both sidesof the path of the sheet material 33, is an atomizer 39 which isconnected by pipes 41 and 43 to suitable sources of water and air orother gas. The atomizer 39 provides an extremely fine and generallyuniform mist or fog of water on or adjacent to the sheet material 33.With sheet materials of substantial width a plurality of such atomizersare preferably employed for laying a water mist along one or both sidesof a sheet material, as illustrated in FIGURE 3. Of particularimportance is that the water which is directed toward and intended to beapplied to the sheet material at this stage must be in the form of auniform and extremely ne mist to avoid spotting of the sheet materialwhich may adversely affect its appearance and/ or physical properties.

Within the chamber 15 and along opposite sides of the path of the sheetmaterial 33 are banks of steam coils 45 and 47, each of which includeslaterally spaced steam headers 49 which are connected by a series ofspaced steam lines or runners 51. Moist steam is delivered into theheaders 49 through a steam line S3 and issues from a series of nozzlesor jets 55 which project from the runners 5l. The steam may bedischarged directly against the sheet material 33. Alternatively, as inthe case of the very absorbent and/ or extremely fragile materials, thedis charged steam maybe diffused by being impinged against baffle slatswhich are supported between the jets 55 and the path of the sheetmaterial.

The runners 51 of each bank of steam coils 45 and 47 are preferablyinclined upward at their centers to insure that condensation within therespective runners is auto-y matically carried down to the headers 49and thence out through suitable steam traps 57 and pipes 59. Thisconstruction assures that no water can be blown out from the nozzles, 55and thereby prevents water spotting on the sheet material. The chamber15 is alsoprovided with heating coils 61y and 63 through which steam orother heated medium is circulated. The coils 61 and 63 are designed tomaintain the atmosphere within the chamber 15 at a suiciently elevatedtemperature to avoid undesired or excessive condensation.y

Located within the chamber 15, along opposite sides of the exit 31, aresuction or exhaust ducts 65 and 57 which are slotted at 69. The ducts 65and 67 are connected -by a pipe 71 to the intake end of a suitableblower or like structure, not shown, and are designed to sepaf rate andremove the spent and excess steam and saturated air from along side ofthe sheet material 33 as it leaves the chamber 15. More important, byexhausting the chamber 15 at its exit end by means of ducts 67 and 69,layers of the applied water mist are drawn into the chamber 15 throughits entrance opening 29 and travel concomitantly with and along theopposite sides of the sheet material as it is being subjected to thesteam atmosphere. If desired, the heating coils 63 and 65 may extendover portions of the exhaust ducts 67 and 69 so as to avoid undesiredcooling and condensation of the moisture car-v ried by the steam withinand along areas surrounding such ducts.

An atomizer or nozzle r73 is provided outside of the humidifying chamber15 along one and perhaps both sides of the path of the sheet material 33as it issues from the exit opening 31.y This nozzle 73 is of the sameconstruction as the atomizer 39 heretofore described and is con-- nectedby pipes 75 and 77 to suitable sources of water and air or other gas.With sheet materials lwhich are of substantial width a plurality of suchnozzles 73 are preferably employed along one and, most usually, alongboth sides of the sheet material. These nozzles 73 each provide anextremely line and generally uniform mist or fog of water on or adjacentto the sheet material.

In operation, the sheet material 33 proceeds over the guide roll 35 andpast the plurality of atomizers 39 where a mist of water is applied onand adjacent to the opposite sides thereof. The sheet material 33 thenpasses through the entrance openingl 29 of the chamber 1S where it issubjected to an atmosphere of moist steam as supplied by the steam lines53, headers 49, runners 51 and jets 55.

The exhaust ducts 65 and 67 and thepipe 71 continuously remove steamfrom Within the chamber 15 and cause layers of water mist to Kbe drawninto the chamber 15 through its entrance opening 29. These layers ofwater mist travel concomitantly with and along the sides of the sheetmaterial 33 as it is advanced through the chamber 15 and penetrate intothe sheet material under the somewhat turbulent and elevated temperatureconditions provided by the moist steam atmosphere. The moisture impartedto the sheet material -by this water mist is, of course, supplemented bythe moisture added by the steam itself so that a `substantial amount ofwater is added to the sheet material during a relatively short treatingstage.

As the now humidilied sheet material 33 issues from the exit opening 31of the chamber 15, it is cooled by the ambient atmosphere.Alternatively, the humidiiied sheet material may be more rapidlycooledby means of one or more chill rollers, such as shown at 37.

In lieu of or in addition to the method described above, the sheetmaterial 33 leaving the chamber i5 may be subjected to a mist of wateras supplied by the nozzles 73. The sheet material 33 at this stage willbe in at least a warm condition and will thus rapidly assume the appliedmist of water as the latter travels in a direction opposite to that ofthe sheet material and toward the exhaust ducts 65 and 67. Since theresidual heat of the sheet material 33 is dissipated during thisprocedure no additional cooling of the sheet material is usuallynecessary.

As heretofore mentioned, the moisture content of the humidified sheetmaterial 33 is greater when subjected to a mist of water before ratherthan after such material issues from the chamber. However, when thesheet material 33 is treated with mists of water both as it enters andissues from the chamber 15, and before it has been cooled, its moisturecontent is greatly and uniformly increased. Moreover, the large additionof moisture to the sheet material by this procedure is not accompaniedby water spotting or any apparent sacrifice in the appearance and/ orphysical properties of the material.

It is to be understood that changes and variations may be made withoutdeparting from the spirit and scope of the invention as defined in theappended claims,

I claim:

1. Apparatus for imparting moisture to hydrophilic materials including achamber having separate entrance and exit openings, means to pass thehydrophilic materials through said cham-ber, means positioned outwardlyof and adjacent to at least one of said chamber openings for applying amist of water on and adjacent to the materials, steam supply means forsubjecting the materials to a steam atmosphere while in said chamber,and suction means located adjacent to the chamber exit opening forwithdrawing the steam atmosphere from within said chamber and causing alayer of water mist to be drawn into the chamber through at least one ofsaid charnber openings.

2. Apparatus for imparting moisture to hydrophilic materials including achamber having separate entrance and exit openings, means to pass thehydrophilic materials through said chamber, means located outwardly ofand at least along one side of at least said entrance opening forapplying a mist of water on and adjacent to the materials, steam supplymeans for subjecting the materials to a steam atmosphere while in saidchamber, and suction means located along opposite sides of and adjacentt0 the chamber exit opening for withdrawing the steam atmosphere fromwithin said chamber and causing at least one layer of water mist to bedrawn into the chamber through said entrance opening and move with thematerials as they travel therethrough.

3. Apparatus as defined in claim 2 further including heating coilsdisposed within said chamber 4. Apparatus as defined in claim 2 whereinsaid means for applying the water mist includes an atomizer,

5. Apparatus as defined in claim 2 wherein means for applying a mist ofwater on and adjacent to the materials are located outwardly of both theentrance and exit openings of said chamber.

6. Apparatus for imparting Imoisture to hydrophilic materials includinga chamber having separate entrance and exit openings, means to pass thehydrophilic materials through said chamber, means located outwardly ofand at least along one side of at least said exit opening for applying amist of water on and adjacent to the materials, steam supply means forsubjecting the materials to a steam atmosphere while in said chamber,and suction means located along opposite sides of and adjacent to thechamber exit opening for withdrawing the steam atmosphere from withinsaid chamber and causing at least one layer of water mist to be drawn ina direction opposite to the direction of travel of the hydrophilicmaterials and towards the chamber exit opening.

7. A method of hun'lidifyinD a hydrophilic material including the stepsof passing the material into a confined humid Vaporous atmosphere at onelocation, removing the material from the confined humid vaporousatmosphere at a location which is separate and spaced from said onelocation, disposing a iine mist of water on and adjacent to the materialoutwardly or" said confined humid vaporous atmosphere at least at one ofsaid locations, and separating the humid vaporous atmosphere from thematerial as the material approaches said separate location.

S. A method as defined in claim 7 wherein said fine mist of water isdisposed on and adjacent to the material only as it approaches said onelocation.

9. A method as defined in claim 7 wherein said fine mist of water isdisposed on and adjacent to the material only as it leaves said separatelocation.

10. A method as defined in claim 7 lwherein said fine mist of Water isdisposed on and adjacent to the material as it approaches said onelocation and also as it leaves said separate location.

11. A method of humidifying a hydrophilic material including the stepsof passing the material into a confined humid vaporous atmosphere at onelocation, disposing a tine mist of water on and adjacent to the materialas it approaches said one location, removing the material from theconlined humid vaporous atmosphere at a location which is separate andspaced from said one location, separating the humid vaporous atmospherefrom the material as the material approaches said separate location, andcooling the material after it is removed from said confined humidvaporous atmosphere.

i2. A method of humidifying a hydrophilic material including the stepsof passing the material into a generally confined atmosphere of moiststeam at one location, disposing a neI mist of water on and adjacent tothe material as it approaches said one location, removing the materialfrom the atmosphere of moist steam at a location separate and spacedaway from said one location, applying suction at said separate locationto remove excess steam and cause a layer of water mist to travelconcomitantly with the material as it enters the atmosphere of moiststeam at said one location, and cooling the material after it is removedfrom the atmosphere of moist steam.

13. A method of humidifying a running sheet material including the stepsof advancing the sheet material longitudinally of itself through a path,subjecting the sheet material to an atmosphere of moist steam as it isadvanced along one portion of its path, applying a ne mist of water onand adjacent to the advancing sheet material as it approaches and entersthe atmosphere of moist steam, separating the moist steam atmospherefrom the sheet material yby suction at a location which is separate andspaced from the location at which such sheet material enters the moiststeam atmosphere and thereby cause at least one layer of water mist tobe drawn with the sheet material as it enters and is advanced throughthe atmosphere of moist steam, and applying a line mist of `water on andadjacent to the advancing sheet material as it leaves the location atwhich it is separated from the moist steam atmosphere.

References Cited bythe Examiner UNITED STATES PATENTS 2,398,856 5/1946Reel 34-155 X 2,718,065 9/1955 Conti 3423 X 2,906,205 9/1959 Speers34-155 X FREDERICK L. MATTESON, JR., Primary Examiner.

JOHN I. CAMBY, Examiner.

7. A METHOD OF HUMIDIFYING A HYDROPHILIC MATERIAL INCLUDING THE STEPS OFPASSING THE MATERIAL INTO A CONFINED HUMID VAPOROUS ATMOSPHERE AT ONELOCATION, REMOVING THE MATERIAL FROM THE CONFINED HUMID VAPOROUSATMOSPHERE AT A LOCATION WHICH IS SEPARATE AND SPACED FROM SAID ONELOCATION, DISPOSING A FINE MIST OF WTER ON AND ADJACENT TO THE MATERIALOUTWARDLY OF SAID CONFINED HUMID VAPOROUS ATMOSPHERE AT LEAST AT ONE OFSAID LOCATIONS, AND SEPARATING THE HUMID VAPOROUS ATMOSPHERE FROM THEMATERIAL AS THE MATERIAL APPROACHES SAID SEPARATE LOCATION.